Rman related question/answer:

 Difference between using recovery catalog and control file?

Old backup information in control file will be lost When new incarnation happens but it will be preserved in recovery catalog.

Scripts can be stored in recovery catalog. Recovery catalog is central and can have information of many databases.

What is the use of crosscheck command in RMAN?

Crosscheck will be useful to check whether the catalog information is intact with OS level information.

What are the differences between crosscheck and validate commands?

Validate command is to examine a backup set and report whether it can be restored. RMAN scans all of the backup pieces in the specified backup sets and looks at the checksum to verify that the contents are intact so that backup can be successfully restored if necessary.

Crosscheck command is to verify the status of backups and copies recorded in the RMAN repository against media such as disk or tape. The crosscheck command only processes files created on the same device type as the channel running crosscheck.

What is the difference between backup set and backup piece?

Backup set is logical. Backup piece is physical.

What is obsolete backup and expired backup?

Expired means that the backup piece or backup set is not found in the backup destination.

Obsolete means the backup piece is still available, but it is no longer needed. The backup piece is no longer needed since RMAN has been configured to no longer need this piece after so many days have elapsed, or so many backups have been performed.

Difference between auxiliary channel and maintenance channel?

New features in Oracle 12c RMAN?

New features in Oracle 11g RMAN?

What is the use of nofilenamecheck in RMAN ?

When NOFILENAMECHECK is used with the DUPLICATE command, RMAN does not validate the filenames during restoration. If the primary database and the standby database are on the same host, The DUPLICATE NOFILENAMECHECK option should not be used.

Do we need to shutdown db to change block change tracking file?

No.

What are all the  database file's that RMAN cannot backup ?

RMAN cannot take backup of the pfile, redo logs, tns or network configuration files, password files, external tables and the contents of the Oracle home files.

Can I take RMAN backup when the database is down ?

No, we can take RMAN backup only when the target database is open or in mount stage.